Speakers are fantastic technological innovations that have had a significant influence on our culture. Nonetheless, they are incredibly straightforward machines at their core.
It’s simple to feel like you’re staring at a black box when you examine a piece of technology like a speaker and wonder how speakers work.
What is concealed within them? It is somewhat true a lot of the time. Yet if you can master just one or two fundamental ideas, you’d be shocked at how far you can go.
The fundamental relationship between electricity and magnetism is one of the ideas that must be grasped to comprehend how something like a speaker functions. I’ll describe how they work in this in-depth article using precise explanations.
The History of Speaker
In fact, early telephone designs by Johan Philipp Reis from 1861 contain the first speakers. These were improved upon in later decades by people like Thomas Edison, Ernst Siemens, and Alexander Graham Bell.
But, the now-ubiquitous moving coil technology didn’t fully take off until the early 20th century. Oliver Lodge first created the concept in 1898, and Edward W. Kellogg and Chester W. Rice successfully patented it in 1925, establishing the fundamental design for practically all speakers in use today.
When producers worked to enhance features like overall power and frequency response in the setting of theaters and huge PA systems, things started to really take off in the 1930s.
Systems with several drivers for various frequency ranges, design uniformity, and better materials for components like the driver cone, magnet, and enclosure were all developments in the 20th century.
How Do Speakers Work?
Here is a detailed explanation of how speakers work:
1) The musical waveform’s representational output voltage starts to rise. From the positive side to the negative side of the speaker’s voice coil, an electrical current begins to flow.
2) The voice coil is surrounded by a magnetic field that has the same polarity as the permanent magnet fastened to the speaker frame. Keep in mind that magnetic fields that are opposite each other repel one another.
3) As the cone/diaphragm moves forward, air pressure is generated, which produces sound.
4) The current increases, the magnetic field strength of the voice coil grows, and the electrical signal voltage increase toward the peak of the sine wave in the musical signal.
5) The cone is further pushed out as a result.
6) After reaching its peak output point, the signal starts to decline. The cone starts to move toward its off (zero voltage) point as the current starts to decrease as well.
7) The cone returns to its initial position when the signal approaches zero (also known as the “zero voltage crossover threshold”).
8) Once the voltage shifts to the negative side, the electrical signal starts to reverse. A magnetic field with a reversed polarity is produced when current travels from the negative voice coil side to the positive.
9) The magnetic field of the voice coil now opposes the permanent magnet attracting it, and the cone starts to move from front to back (instead of the original rear to front).
10) The cone rotates backward as the signal continues, producing the opposite of the sound waves produced by air movement.
11) As soon as the stereo or amplifier output voltage reaches zero, the next audio signal starts playing and the cycle repeats itself.
In a sense, speakers are merely a form of electric motor that converts an electrical signal into a mechanical output—moving air to produce sound—by using it as power.
What’s Within A Speaker?
The following components, which are found in most speakers, work together to produce sound:
Permanent Magnet – To enable movement, a magnet is employed to provide a constant magnetic field around the voice coil.
Voice Coil and Bobbin – A cylindrical tube is known as the bobbin is fastened to the cone’s base. The voice coil is an extremely long and tightly wrapped wire coil that receives electricity from an amplifier’s musical output, which travels through it to produce a magnetic field.
Spider or Suspension – The voice coil bobbin assembly is supported by the thin, wavy-shaped woven material known as the spider, which also aids in pushing the cone back into position when it shifts.
Cone & Dust Cap – This rigid cone-shaped material is moved by the voice coil and magnet working together to move air and produce sound. To keep dirt and dust out of the opening in the center, a thin piece of material called the dust cap is placed over it.
Speaker Basket – The basket, which the speaker pieces attach to and which maintains alignment, is a cast metal or stamped metal frame. Moreover, it offers a method of mounting the speaker assembly to a box.
Speaker Terminals & Braided Wire – The speaker wire is connected to the speaker by speaker terminals, which are metal tabs or connectors. They use a flexible braided wire that moves with the cone to connect to the voice coil.
Surround – The material holding the top edge of the cone to the basket is flexible and strong, typically rubber or a sort of foam.
Why are Speakers Fitted in Boxes?
Speakers are fitted in boxes for a variety of reasons. Firstly, the box helps to reduce any sound waves emitted from the back of the driver, which could interfere with the sound being produced from the front. This is known as ‘acoustic loading’ and it helps to make sure that all of the sounds are coming from one direction.
Secondly, boxes help to increase the bass response by trapping low frequencies inside them, so they can be heard more clearly. Finally, boxes also act as an amplifier for low frequencies by creating an internal resonance cavity that amplifies these sounds. This helps to create a fuller, richer sound overall.
Why are there Holes in Some Speakers?
Many speaker boxes include circular holes or slots, usually on the front or back, as you may have seen. You may recognize a bass reflex enclosure by the ports or vents you can see in it.
Similar to how a note is produced when air is blown over an open bottle of beer, a bass reflex enclosure operates similarly. Because the volume of air inside the bottle changes as the number of liquids changes, the note also changes.
The note would also change if you were able to expand the bottle’s glass neck. It is a resonant system that can be tuned by changing the enclosure volume or the port dimensions.
If adjusted properly, this extends the system’s bass performance by producing a resonance just below the point at which the loudspeaker response would typically roll off. The port tuning must be calculated for the exact driver in the specific enclosure in order for this to function properly.
Even though the cone diameter of the new driver is the same, the box and port tuning will no longer be suitable, and the sound quality will suffer.
The basic operation of passive radiator loudspeakers is the same, but the bass resonance is produced by the enclosed air volume and a mass-loaded, unpowered speaker cone.
Why are Magnets Found in Speakers?
Electrical current is used by all speakers and amplifiers to produce sound. Magnetic fields are created when electrical current undergoes a transformation. Built-in magnets are used to create a magnetic field that opposes the magnetic field of the electrical current, causing the speaker’s cone to shake. We perceive sound because vibrations are produced when two magnetic fields that are opposed to one another repel one another.
What Increases a Speaker’s Volume?
The volume of a speaker depends on how much power is passed through it when it is in use. The power going through any amplifiers you have will also increase the volume. Its loudness is further affected by additional elements like speaker size, insulation, and speaker cone reflex.
Hence, if you want to increase the volume of your speaker, make sure it is big, has a compact, tight cone, and has sufficient insulation. It should also have the appropriate wattage.
How Often Do Speakers Vibrate?
The design of the audio system, specifically the audio signal frequencies present in the audio drivers, affects the frequency or rate of a speaker’s vibration. Most speakers can vibrate within an audible range with reduced bandwidth, and the sound range typically ranges from 20Hz to 20 kHz.
Final Thought
Speakers are a vital part of any audio system and understanding how do speakers work is key to getting the most out of them. From the basics of how speakers take an electrical signal and transform it into sound waves, to the importance of power, quality materials, and tuning, knowing these components can help you make the best choice when buying speakers. With this knowledge in hand, you’ll be able to find the perfect speaker system for your needs and get great sound from your audio setup. Whether you’re upgrading your car’s audio or want to fill your home with sound, understanding how speakers work is essential for enjoying great audio quality.
